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Old 27th August 2005, 23:42   #29  |  Link
bond
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Join Date: Nov 2001
Posts: 9,770
Quote:
Originally Posted by DeathTheSheep
If you wish your video to maintain a specific, constant quality the whole way through, use only the Constant Quality feature of 1-pass mode.
<> Do not use a quantizer of under 15 unless you are working for archive/reproduction quality.
<> Also, do not use anything over 40: the quality is simply unbearable unless you are encoding from an extremely sharp source of high-contrast edges and plan on streaming it over the internet.
<> A good bet for most people interested in high quality video would be the range of 22-30 (or, more specifically, 24-28). Of course, this varies depending on individual taste and how much free space you have.
<> On animated content with few detailed textures, consider using a higher quantizer.
<> On "real-life" content, especially that with many dark scenes and important subtle textures, consider using a much lower quantizer value.
where do these values come from? any screenshots?

why do you think that its a bad idea to trust x264 on deciding what quant to use? any samples which show that x264 does a bad decision on that?

Quote:
To stream x264 video, you need to have a player capable of handling streaming; nearly all players I can think of at the moment support this. I suggest using Media Player Classic, but Windows Media Player 9/10 works just as well for many people as long as the ffdshow decoder is installed. Make sure to configure the player to automatically start a stream with the desired file extension (the most commonly made x264 files use the ".avi" extension).
you are sure that dshow players will be able to play streamed h.264 .avi files? somehow i cant believe this. do you have a sample stream link i can try?

Quote:
<> Use 0 references. Reference frames cause a lot of hop-skipping around the stream. If a certain frame's reference is far off into the file, the entire file becomes unplayable until the video is downloaded up to that reference.
i doubt you mean 0 references, as this would mean using an i-frame only stream. what you mean here is using 1 reference frame

Quote:
<> Use a maximum of 1 B-frame. It is NOT recommended to use consecutive B-frames on very-low bitrate content. I have proven this with the thread entitled "The Coolness of B-Frames." The WORST place to use a B-frame in H.264 (or many other formats for that matter) is on low-bitrate, low framerate, streaming, animated content.
well i wouldnt call this to be proven at all, after all the purpose of b-frames is helping in low bitrates too...

Quote:
<> 4-5 references are the typically accepted maximum. However, if you have a little bit of extra time on your hands (or a beefy computer), consider using up to 8 references (which decode just about as fast as 5, according to my Pocket PC AVC benchmarks).
my psnr comparisons showed that references over 5 dont really bring any quality increase but will slow down decoding

Quote:
<> B-frame reduction (if you choose to use B-frames) should be adjusted according to the desired datarate. For most DVD backups, the default B-frame reduction of 30% seems to be sufficient. However, with certain animated medium bitrate content, I suggest use of up to 50% B-frame reduction.
why dont you think that the default values of x264 are ok? any sample files which show that default setting in x264 does a bad job or that your proposal does a better job?

Quote:
<> Don't ever use CAVLC... My benchmarks prove that decoding CABLC streams is only slightly faster than CABAC
not true, cabac will decrease decoding speed clearly, as i described here

Quote:
<> Personally, I find that the keyframe threshold of 45% and keyframe QP boost: 20 to be the optimal in achieving quality at medium bitrates. However, if you wish to produce Ultra-Low-Bitrate video (DVD backups less than one CD), consider reducing this to 0, for your video's quality (PSNR) per BM will increase.
again my request for samples that show that x264s defaults perform worse than with your proposal

Quote:
However, if you have a particularly complex source (or if you really want to scrimp for the best possible quality), try Uneven Multi-Hexagon with a ME range of 16-32
hm didnt pengvado write somewhere that it doesnt make sense to use a value higher than 16 and that it even could decrease quality!?

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Generally lower framerates (12-15 as opposed to 23.976-29.97) need a higher estimation range.
why that?

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<> In maximum-quality content, I find that the keyframe threshold of 35% and keyframe QP boost of either: 30 or 0 to be the optimal in achieving quality at medium-high bitrates in my "maximum possible quality" mode.
again my request for samples that show that x264s defaults perform worse than with your proposal

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<>\ When they become more widely available for use, take advantage of custom H.264 quantization matrices. The x264 codec currently (rev. 285) does not support this feature.
it does

Quote:
*B-frames can be activated in "pyramid" mode, which allows B-frames to serve as references. If you wish to use a lot of references (and thereby increase quality slightly), consider selecting the "Use as references" checkbox.
b-pyramid doesnt really have much to do with the number of reference frames

Quote:
However, this option may cause some crashes with both the encoder and the decoder (if either is old enough). For this reason, I recommend NOT using B-frame references.
doesnt make sense, instead you should recommend to always use the latest version of the codec

Quote:
<> For deblocking strength, try not go out of bounds of the -3 to 3 range. Generally, any more than 3 will turn your result into mush while decreasing PSNR and actually increasing the output file slightly. Any less than -3 may cause the result to look a bit too blocky and any lack of texture will merely become more apparent as all smoothing is taken out.
positive values of loop will tend to remove details -> smaller filesize

Quote:
Present in certain AVC encoders, this is a method of lumi (+chroma) masking in which very light or dark areas of a scene are encoded in terrible quality, which gives more bitrate to the rest of the video.
i wouldnt talk about "terrible quality" here, as the point here is to encode with lower bitrate where the eye cant see the difference anyways, so for the eye the quality will stay the same

Quote:
<> The main determining factor in whether or not you would like to enable Psychovisual Enhancements is the darkness of your source. In films with very dark scenes (dungeons, tunnels, night, shadow), turn this OFF for good measure. If the source isn't very dark, I'd recommend you try light enhancement. Strong psychovisual enhancement can lead to problems (the codec might think important semi-dark things are "dark enough" to heavily reduce the quality, which may be obvious to the viewer). Check out CiNcH's post below for more info...
you are talking here mainly about nerodigital as x264 doesnt do psy, any link to information about how psychovisual enhancments work in nerodigital so i am able to find out whether nerodigital really does the lumimasking you describe and not something else?
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